reagarding usage of can and could

[Sharath]

Hi
I'm Sharath from INDIA.I'm just register to this website.

I want to know usage of could and can. How I can  use these words while requesting?
For example, Please see the following statement
1) "Can you speach with abc"  OR  "Could you speach with abc"
  In above statement which is correct or appropriate to use while requesting somebody ?

2)"Could you pls forward this message?" or can you pls forward this message?"  
       In above statement which is appropriate?

what does mean "add a poll" that is present in ur site.

I hope you wil clear my doubts. If any materials(document) is there pls send it to my email address.( urssharath@rediffmail.com or rack_solid@yahoo.co.in )

Thanking you
Sharath

[Keo Somala]

As far as I am concerned, your question can be cleared. You know, this is a problem between using "can" and "could". All your sentences are correct, and there is just a small difference between them. The difference is "could" is used for requests in a more polite way than "can". Usually, we use 'can you...?' with other close friends or other people we know very well. But of course, we use 'could you...?' more politely like with other teachers or according to whom you talk to.

Have  a nice day!
Kounila